Abstract: A new application language called the MAWL language and a compiler for the new application language called the MAWL compiler are provided for use by programmers of World Wide Web services. The MAWL language and the MAWL compiler may be used to provide any World Wide Web service, but they are especially useful for programming interactive services. The MAWL language provides an expressive typing capability. Through this expressive ability World Wide Web services that have defined states, sequences and sessions are straightforward where previously such capabilities do not exist. Further, the MAWL compiler performs error checking for common errors and self-consistency before actual compiling so run-time error checking is avoided. Together the MAWL language and the MAWL compiler greatly increase the productivity of the World Wide Web programmer and the complexity of the World Wide Web services that can reliably be provided.